• The Role of MOIRE Techniques in Precision Technical Applications

Abstract

The applications of the moiré patterns based on two gratings, methods were recently developed where circular, radial zone or other types of gratings are used. Moiré patterns formed by the interferences of circular gratings present the advantage of yielding, besides conventional information extracted from any moiré pattern formed by line gratings a complete information concerning the definition of the vector of the displacement of the one grating relative to the another. The moiré pattern formed consisted of parallel line fringes or family of circles. The moiré gauges created by the interference of either two circular gratings of a circular and line grating or radial moiré gauges, when fully developed may successfully compete with electric or photo electric strain gauges, All moiré techniques are easy and simple to apply. They do not necessitate elaborate equipment at the mose four photographs of moiré patterns after each loading suffice for a complete and accurate evaluation of the stress and strain in which the specimen is subjected